sigma 90mm f2.8 macro

hi need help with a sigma 90mm f2.8 macro lens on a 7d,the auto focus works but the aperture doesnt seem to work it is always f2.8 and if i set the camera to manual and try to adjust it the camera gives me a error code 01

well it dosnt say di on it so i guess the older one

Sigma does not have a 90mm macro lens. I guess you have an older version of Tamron. There could be compatibility problems with older lenses made for film cameras and newer dSLR bodies. Several Sigma lenses have this problem and Sigma provided free re-chipping. I don't know whether Tamron has a similar service but you should enquire with the company.

ken wrote:

well it dosnt say di on it so i guess the older one

I think Jay (like Gautam) has assumed you meant the Tamron 90mm macro, because it's the only 90 mm macro lens currently available. I'm saying this because the DI question refers to Tamron, not Sigma.

However I suspect you do mean the long-discontinued Sigma 90mm macro and haven't made a mistake. If so, I'm afraid most (possibly all?) Sigma lenses of that vintage don't work correctly on Canon DSLRs.

The reason apparently is that Sigma doesn't licence the communication protocols in Canon's EOS technology, instead it reverse-engineers them. Reverse engineering is a jargon term for educated guesswork - this means that while Canon has ensured backward compatibility with every EF lens ever made, there can be no such assurance with Sigma. As Gautam explained, Sigma used to replace the electronics in their lenses to make them compatible with present-day cameras, but I haven't read of anyone having that done for a long time.

Knowing this doesn't put me off buying Sigma lenses by the way - I have two - but it is important to be aware of it when buying used, or banking on using an old lens you have left over from a film camera. And buying Canon is not a guarantee of backward compatibility - all the Speedlite flashes prior to the EX series don't work with DSLRs.

Steve Balcombe wrote:

ken wrote:

well it dosnt say di on it so i guess the older one

I think Jay (like Gautam) has assumed you meant the Tamron 90mm macro, because it's the only 90 mm macro lens currently available. I'm saying this because the DI question refers to Tamron, not Sigma.

However I suspect you do mean the long-discontinued Sigma 90mm macro and haven't made a mistake. If so, I'm afraid most (possibly all?) Sigma lenses of that vintage don't work correctly on Canon DSLRs.

The reason apparently is that Sigma doesn't licence the communication protocols in Canon's EOS technology, instead it reverse-engineers them. Reverse engineering is a jargon term for educated guesswork - this means that while Canon has ensured backward compatibility with every EF lens ever made, there can be no such assurance with Sigma. As Gautam explained, Sigma used to replace the electronics in their lenses to make them compatible with present-day cameras, but I haven't read of anyone having that done for a long time.

Knowing this doesn't put me off buying Sigma lenses by the way - I have two - but it is important to be aware of it when buying used, or banking on using an old lens you have left over from a film camera. And buying Canon is not a guarantee of backward compatibility - all the Speedlite flashes prior to the EX series don't work with DSLRs.

The Sigma 90mm is the predecessor of the Sigma 105mm macro. I have a manual focus one from my old Olympus OM film SLR system. It was a very nice compact macro lens, solidly built and with very nice image quality. I think the problem is that it only went to half-life size and you had to use a converter (powerful close-up lens) to get to 1:1 (life-size) - well at least this is the case with mine. As it is such a nice little lens I thought of getting one of the cheap used EOS fit ones you see advertised. However, I found out that it was one of those Sigma lenses that doesn't work on the newer Canon DSLRs. I'm not sure if all the older EOS fit Sigma lenses don't work on the Canon EOS DSLRs, but certainly on some of the well known ones like the Sigma 300mm f4 Apo and 400mm f5.6 Apo this is a known problem. Sigma did re-chip some of these lenses for a while and so these ones will work with the Canon DSLRs, however after a while Sigma stopped re-chipping them and the necessary chips are no longer available. I think these Sigma lenses worked on some of the first Canon DSLRs, but then Canon changed their lens/camera interface, and while it didn't cause problems with Canon lenses, it did with some independents such as Sigmas.

Gautam Majumdar wrote:

Sigma does not have a 90mm macro lens. I guess you have an older version of Tamron. There could be compatibility problems with older lenses made for film cameras and newer dSLR bodies. Several Sigma lenses have this problem and Sigma provided free re-chipping. I don't know whether Tamron has a similar service but you should enquire with the company.

As others pointed out, it is a Sigma 90mm. The do exist.

ken wrote:

hi need help with a sigma 90mm f2.8 macro lens on a 7d,the auto focus works but the aperture doesnt seem to work it is always f2.8 and if i set the camera to manual and try to adjust it the camera gives me a error code 01

Older Sigmas have an electrical problem, where things go wrong the moment the lens tries to close the aperture. The Canon DSLRs got to be more strict about the signals, and the older Sigmas ceased to work properly.

At the beginning of the problem (around 2003 I believe), Sigma offered to replace the electronics boards of lenses. Now they are not able to anymore (no spare parts).

So, there are only three things you can do:

* Use the lens as 90mm portrait lens, wide open. Will give nice subject separation.

* Close the lens to an aperture you can live with, on a film body. Something like f5.6 or f8 or f11, depending on which DOF you find to be the best compromise for your uses. Close the aperture with the button on the camera body, and while keeping it closed, take the lens off the camera. Tape off all contacts of the lens, and use it as manual focus macro lens with fixed aperture. You can of course set another aperture at some point, on the film body.

* Look for another macro lens. My suggestions for those: Tokina 35mm f2.8 DX Macro, Tamron 60mm f2 Di II macro, Sigma 70mm f2.8 EX DG macro, Tamron 90mm f2.8 Di  macro/Di VC macro, Canon 100mm f2.8 USM macro/L IS USM macro, Sigma 105mm f2.8 EX DG OS HSM macro, Sigma 150mm f2.8 OS macro, Sigma 180mm f2.8 OS macro, Canon 180mm f3.5 L USM macro, Tamron 180mm f3.5 Di macro. Pick your favorite focal length/field of view from those.

I have a 90mm Sigma 2.8 Canon mount and it will autofocus on a Canon T2i, but gives an error reading about cleaning the lens contacts, apparently the information does not communicate between camera and lens correctly.  I put the lens on a Canon 5D, the original, and it seemed to work fine.